Officials in Mexico say six men suspected of stealing radioactive material have been detained and are being tested for possible radiation exposure in a hospital.

A health minister for central Hidalgo state, Pedro Luis Noble, says some of the men are experiencing nausea and dizziness, a possible sign of radiation poisoning. Officials say the suspects are under police guard in a Hidalgo hospital.

Friday's news comes hours after authorities said they had recovered all of a stolen shipment of highly radioactive cobalt-60 that was abandoned in a field in central Mexico.

Nuclear waste stolen from town of Tepojaco, north of Mexico City.

A truck carrying the dangerous radioactive material was found Wednesday with the cobalt-60 removed from its protective container.

The material had been removed from obsolete radiation therapy equipment at a hospital in the northern city of Tijuana and was being transported to a nuclear waste facility near Mexico City.

Officials say there was nothing to indicate the thieves were after the cobalt and most likely wanted the white 2007 Volkswagen cargo vehicle with a moveable platform and crane. They say the transport company did not follow proper procedures and should have had GPS and security with the truck.

The International Atomic Energy Agency has called the radioactive material "extremely dangerous.''

Officials say the material did not appear to have been damaged and there was no sign of contamination to the area, but a family that found the container is under medical observation.

The atomic energy agency said "it would probably be fatal to be close to this amount of unshielded radioactive material for a period in the range of a few minutes to an hour.''